Homovanillic acid and 5-hydroxyindoleacetic acid in human brain areas at autopsy. Effect of pre-death conditions with special attention to the state of consciousness and metabolic diseases

HVA and 5-HIAA levels have been assayed by fluorimetric method in medulla oblongata, griseum centralis pontis, substantia nigra, red nucleus, lamina quadrigemina, caudate nucleus, and lenticular nucleus of 21 patients deceased from non-neurological diseases. Levels of both acids were not affected by varying necropsy intervals, but HVA levels decreased with increasing age. Regardless of age, patients who deceased after prolonged coma showed increased 5-HIAA levels in all brain stem areas, especially in medulla oblongata. Such an increase was strikingly high in patients with hepatic coma but less pronounced in diabetic coma. HVA levels were increased in medulla oblongata of patients with hepatic coma, in all brain stem areas after diabetic coma, and were decreased in substantia nigra of comatose patients of various etiologies. L-dopa therapy induced a remarkable HVA increase and did not affect 5-HIAA levels in all areas of patients with hepatic coma.